September 6, 2012

Hubble Image Shows Off Pair Of Galaxies

The Hubble Space Telescope has taken a portrait of two different galaxies forming a peculiar galaxy pair called Arp 116.

The image released today shows the dramatic differences in size, structure and color between spiral and elliptical galaxies.

Arp 116 is made up of a typical elliptical galaxy known as Messier 60, and a smaller spiral galaxy called NGC 4647.

Messier 60 is a typical elliptical galaxy, but together with its adjacent spiral, the two give astronomers a spectacle to see.

Messier 60 is very bright, and is the third brightest in the Virgo cluster of galaxies, which is a collection of over 1,300 galaxies.

The elliptical galaxy is noticeably larger than its neighbor, and has a higher mass of stars as well. Messier 60 has a golden color because of the old, red stars in it, while NGC 4647 has many young and hot stars that glow blue.

Astronomers have been trying to determine whether these two galaxies are interacting with each other, but so far have come up short on evidence.

Although the two galaxies seem to overlap from Earth, there isn't anything to assume that the pairs of galaxies are interacting.

When galaxies interact, the mutual gravitational pull that the galaxies exert on each other disrupts gas clouds. This disruption can cause gas clouds to collapse, forming a sudden burst of new stars.

Although the pair of galaxies do not appear to be interacting this way, studies of very detailed Hubble images suggest the beginnings of some tidal interactions between the two.

Messier 60 was first discovered by three different astronomers in 1779, including: Johann Gottfried Koehler of Dresden, who first spotted it on April 11 that year while observing a comet; the Italian Barnabus Oriani, who noticed it a day later; and the French Charles Messier who saw it on April 15.